וָאָעִ֣ידָה בָהֶ֗ם וָאֹמְרָ֤ה אֲלֵיהֶם֙ מַדּ֜וּעַ אַתֶּ֤ם לֵנִים֙ נֶ֣גֶד הַחוֹמָ֔ה אִם־תִּשְׁנ֕וּ יָ֖ד אֶשְׁלַ֣ח בָּכֶ֑ם מִן־הָעֵ֣ת הַהִ֔יא לֹא־בָ֖אוּ בַּשַּׁבָּֽת׃ (ס)
Then I forewarned them, and said unto them: ‘Why lodge ye about the wall? if ye do so again, I will lay hands on you.’ From that time forth came they no more on the sabbath.
Read midrashic interpretation of Nehemiah 13:21: and classical rabbinic exegesis.